With the small limited recoil case 6ARC I personally don't see a need for a brake. To each their own.
A tuner can and in most cases that I have seen will help but only if the load has been worked up and developed to the best of the ability to perform top accuracy. The added important key to using a tuner is spending time with it testing and paying attention to atmospheric changes when changing settings to figure out why and how much to turn it.
Adding a tuner will NOT within itself magically make your rifle or the load perform better unless time is spent in the learning curve. Lastly, if the rifle, load, & shooter are not capable of wringing the best accuracy out of the set-up then the tuner will probably serve better as a paper weight on the reloading bench.
One of the best pieces of info tuner related is this video with Tim Sellars on Believe the Target